Thursday, February 13, 2014

8051 microcontroller - 13 bit timer (mode 0) a relic from the Intel 8048 microcontroller

The 13 bit timer (ie, timer mode 0) is rarely used these days in 8051 uc based applications. The only reason  there is such a timer mode is to maintain compatibility with its predecessor the Intel 8048  microcontroller (Intel MCS 8048 family).

The 8048 had a divide by 32 prescaler, so the Intel guys set up the mode 0 of 8051 timer with lower five bits of TLx register acting as divide by 32 element which is then cascaded to the 8 bits of THx to give a 13 bit timer.

Microcontroller: Features and Applications  By D. S. Yadav, Arun Kumar Singh

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